Allyl alcohol, which is available commercially from isomerization of propylene oxide, is widely used to make allyl ether, ester, and carbonate derivatives such as, for example, diallyl phthalate and diethylene glycol bis(allyl carbonate).
Poly(allyl alcohol) is known, but it is difficult to prepare, and its usefulness is limited by its poor solubility in most common organic solvents. For example, poly(allyl alcohol) is soluble in alcohols, but is generally insoluble in ethers, esters, ketones, glycol ethers, and hydrocarbons. Solubility in water is also poor, except for hot water. Consequently, poly(allyl alcohol) has limited utility as a chemical intermediate.
Copolymerization of allyl alcohol with vinyl monomers is a potential way to make polymers having a high content of primary hydroxyl groups. Allyl alcohol copolymerizes with some vinyl monomers. However, because allyl alcohol is typically much less reactive than most common vinyl monomers (such as styrene), it is difficult to prepare allyl alcohol copolymers that incorporate a useful proportion of allyl alcohol recurring units. See, for example, U.S. Pat. Nos. 2,894,938 and 2,940,946. Thus, few allyl alcohol copolymers are widely used commercially in spite of the recognized value of polymers having a high content of primary hydroxyl groups.
Propoxylated allyl alcohol can be made by reacting allyl alcohol with propylene oxide in the presence of a basic catalyst, as described for example, in U.S. Pat. Nos. 3,268,561 and 4,618,703, and in J. Am. Chem. Soc. 71 (1949) 1152. Adjusting the ratio of allyl alcohol and propylene oxide to keep the average number of oxypropylene units in the propoxylated allyl alcohol at less than about 2 gives propoxylated allyl alcohol that is readily purified by distillation. In copending application Ser. No. 08/098,114, we described copolymers of these propoxylated allyl alcohols and vinyl aromatic monomers, and the use of the copolymers for polyurethanes, coatings, and unsaturated polyesters.
Still needed in the art are new hydroxyl-containing polymers. In particular, formulators need polymers that have a high concentration of hydroxyl groups, yet still maintain good solubility in water and/or a wide range of common organic solvents. Preferably, the polymers could be easily prepared, and would overcome the solubility limitations of available hydroxyl-containing polymers such as poly(allyl alcohol). The ability to adjust the solubility characteristics of the polymers to suit a particular end use would be valuable, and would greatly expand the potential use of these polymers in many polymer applications, such as polyurethanes, polyesters, alkyds, uralkyds, polyamines, and acrylates.